Method for treating cocoa beans



Nov. 10, 1936.

A. LAgsslG METHOD FOR TREATING COCOA BEANS Filed Feb. 5, 1934 2 Sheets-Sheet 1 Nov. 10, 1936.

YA. LAEsslG METHOD FOR TREATING COCOA BEANS Filed Feb. 5, 1934 2 sheets-sheet 2 Lwenzor:

Patented Nov. 10, 1936 .UNITED 1STATES METHOD FOR4 TREATING COCOA BEANS Alfred Laessig, Halle on the Saale, Germany Application February 5, 1934, Serial No. 709,888

In Germany February 18, 1933 4 Claims. (Cl. 99-23) `dried or roasted by a current of hot air generated by an air heater. The intake for the fresh air supplied to the heater opens into one or more of the lower sets of lcuvres thus cooling the hot beans in addition to preheating the incoming fresh air.

In order to obtain a further improvement an apparatus for fermentation, oxidation and drying of cocoa beans shall-be so designed that it enables operations to be conducted in a continuous manner.

Apparatus according to the invention is shown by way of example ln the accompanying drawings in which:

, Fig. 1 is a 'sectional elevation of a complete plant for the preparation of cocoa beans,

Fig..2 is a vertical sectional view of the dryer on a larger scale;

In the apparatus according to Figure 1, the cocoa beans to be improved are fed continuously by a worm I, to a washing machine 2 from which they pass through a shute 3, onto a travelling lattice belt 4 running at a low speed in a tank 5 charged'with a fermentation liquid, and in such a manner that the beans remain inthe tank 5 for one to three hours, to ensure thorough steeping. Keeping the beans in the liquid for a-l dryer which consists of a vertical dryer -casing i 8 provided with louvre surfaces 9., which are disposed in angular relation to one another and are open at the sides. The beans leaving the aera-l tion vessel pass slowly down between these louvre plates 9, which distribute the beans in the form of a thin and loose layerso that they can be well aerated for the purpose of dryingor roasting.

The dryer casing 8 is divided by transverse PATENT OFFICE walls I0 into the heating stages I and II. The beans are dried by means of hot air generated in the heater II and admitted first in the bottom stage I, which in the drawings is traversed from right to left by the air current. In the succeed- 5 ing stage II the air ows from left to right. The air is moved by the fan I2 which draws it out of the stage II by way of the pipe I3 and discharges it through the conduit III.

The two-stage louvre dryer operates on the counterow principle inasmuch as the .already pre-dried beans in the stage I come into contact with the hottest and driest air, while the still damp beans in the stage II encounter air that has already been cooled and moistened in stage I. 15 v The intake I5 for the fresh air suppliedto the heating apparatusv II of the dryer opens into one or more of the lower sets of the louvre plates 9, thus cooling the hot beans in addition to preheating the incoming fresh air. 2o

'I'he air-heater, which may be used, has a nest of tubes I6, the end portions of which are fitted i into end-chambers Il and I8 respectively.

The most suitable temperature for this drying with warm air lies between 72 C. and 74 C. 25

The dryer is connected with the aerating vessel 1 by means of the conduit I4, so that the Warm air leaving the dryer is fed to the shaker sieve 6, Where it passes transversely through the layer of beans in the direction indicated by the arrows. l

A special advantage of this aeration apparatus l consists inthat the oxidation process requires only'a very short time for completion. Given a shallow layer (for example 15-20 mm.) of beans and aA shaker sieve about 2 metres wide, the aerating process is complete in about 15 minutes.

The dryer` is provided With an outlet I9 for the dried and cooled' beans,` which then are passed by a worm 20 to a cracking and husking mill not shown in the drawings'. The outlet I9 is provided with a regulating damping device 2l.

I claim:

1. A method of treating cocoa beans which comprises the continuous and successive steps of steeping the beans in a 'fermentation liquid, aerating and shaking the Wet beans during horizontal travel in a. thin layer on a shaker sieve to complete the oxydation of the beans, and then submitting the beans to a three-stage drying and roasting in a louvre dryer during substantial vertical and `constant rolling vtravel in which in the rst stage after the beans are aerated the beans are treated by hot air, in the second stage they are treated with hot air at a higher tem- 55 peratuie than the goreeediiig, and in 'the stage the beans vare cooied 'oy air at room temperature.

2. A method according to claim l, in which the three-stage drying and roasting is carried out by forcing the air threugh and around the beans at angles relative to the vertical travel of the beans.

3. Pi. method according to claim l, in Whici the three-stage drying and roasting is carried out by forcing the air through and around the beans at angles relative to the vertical. travel of the beans and in which the air enters at the third stage, is preheated just before entering the second stage, passes then through the rst stage and finally thropgh the beans in the aeration and shaking step.

plete the oxydation o.

is. method o ti eine means which comprises a continuous successive step of washing the steep-ing 'the beans in a fermentation liquid hy slot/,fly drawing the beans through the iiquid on a traveling beit, eert-,ting and shaking the wet beans during horizontal travel in a thin layer on a shaker sieve to comi, e heans, and then suhmitting the beans stage drying and .roasting .in a iouvre di t during substantial vestical and constant rolling travel in which in the rst stage after the beans are aero-ted the beans are treated by hot aiigin the second stage they are treated With hot at a higher temperature than the preceding, and in the third stage the beans are cooled by air at room temperature.

ALFRED T.LaESSIF. 

